an assembling or coming together of a number of persons, usually for a particular purpose

The principal will speak to all the students at Friday's assembly.

a group of persons gathered together, usually for a particular purpose, whether religious, political, educational, or social.

( often initial capital letter ) Government . a legislative body, esp. the lower house of the legislature in certain states of the U.S.

a bill before the assembly; the New York State Assembly.

Military .

a signal, as by drum or bugle, for troops to fall into ranks or otherwise assemble.

the movement of forces, tanks, soldiers, etc., scattered by battle or battle drill, toward and into a small area.

the putting together of complex machinery, as airplanes, from interchangeable parts of standard dimensions.

Machinery . a group of machine parts, esp. one forming a self-contained, independently mounted unit.

noun

accumulation , aggregation , assemblage , association , band , body , bunch , clambake , cluster , coffee klatch , collection , company , conclave , confab , conference , convocation , council , crew , crowd , faction , flock , gathering , get-together , group , huddle , mass , meet * , meeting , multitude , rally , sit-in * , throng , turnout * , adjustment , attachment , building , connecting , construction , erection , fabrication , fitting together , joining , manufacture , manufacturing , modeling , molding , piecing together , setting up , shaping , welding , congregation , congress , convention , muster , troop , audience , auditorium , caucus , concourse , consistory , conventicle , diet , forum , galaxy , hall , junta , legislature , parliament , party , session , society , synod , tribunal